The Census European Hub Project aims to establish a new system for disseminating 2011 census data on the Eurostat website using SDMX standards, enhancing flexibility and access to detailed, comparable data across EU member states. The pilot project, initiated in collaboration with several countries, explores the implementation of this system through data sharing, enabling countries to provide easily accessible census data via a central hub. The project is expected to reduce production costs, improve infrastructure, and facilitate the use of international standards in data management.

1. The Census European Hub Project Workshop on Data Transmission 17-19 June Becici - Montenegro Vincenzo PATRUNO

2. Overview It's the proposal of a new system to achieve the publication of the 2011 Census data on Eurostat website using SDMX standards

3. Overview Census taking is a very cost intensive exercise justified by the unparalleled quality of the result. Important aspects of that quality are: The flexibility to cross tabulate different variables

4. An easy access to data

5. Detailed data methodogically comparable

6. Overview F L E X I B I L I T Y HAR MO NI ZA TION

7. Access to detailed Census data that are methodologically comparable among the Member States and structured in the same way Harmonization

8. Final user should have the possibility to cross tabulate different variables Flexibility

9. The Goals The dissemination of the result of the censuses in the EU should reflect those advantages to the highest possible extent.

10. The Traditional Approach Member States provide microdata to Eurostat. Eurostat aggregates microdata and stores obtained data in a central repository. This repository will be used for data dissemination Member States provide predefinited tables to Eurostat. Eurostat publishes those tables on its website 1 2

11. Approach (1) maximises flexibility in offering data to final users. But: – Aggregation functions on the central system could be very difficult to implement due to: • different confidentiality rules to be applied to microdata from different Countries; • whether data come from a "full" census (conventional or register-based) or from a sample survey. – Data maintenance could be very cumbersome because every time a revision is issued, an entire set of microdata needs to be updated or replaced. The Traditional Approach

12. Approach (2) greatly simplifies the exercise But: It doesn't offer enough flexibility to final users, who would have limited possibilities to tailor data to their information needs. The Traditional Approach

13. The Traditional Approach NSIs EUROSTAT

14. We have normally two different approach to exchange data: PUSH and PULL Push and Pool

15. PUSH mode means that the data provider takes action to send the data to the party collecting the data. PULL mode implies that the data provider makes the data available via the Internet. The data consumer then fetches the data on his own initiative. Push and Pool

16. SDMX is primarily focused on the exchange and dissemination of statistical data and metadata. SDMX promotes a “ data sharing ” model to facilitate low-cost, high-quality statistical data and metadata exchange. Data Providers publishes the availability of data/metadata to Data Consumers and the latter are responsible for fetching the data/metadata at will. . Data Sharing Model

17. Data-sharing only works if there are standard formats

18. Like the Web itself, a data-sharing model relies on pull exchanges, not push exchanges Data consumers discover the data they need, and its location, and then go and get it

19. Data producers don’t have to send data Notes about Data Sharing

20. The Census Hub is based on the concept of data sharing : A group of partners agree on providing access to their data according to standard processes, formats and technologies The Census Hub Idea IT, IE, DE, PT, MT, SI, EE, BG Countries involved GB, ES and GR Additional Countries involved before the end of the year

21. SDMX standards support the "pull" mode of data sharing, where the collecting organization retrieves the data from the providers' web servers. The data: may be made available for download in a SDMX-conformant file

22. may be retrieved from a database in response to an SDMX-conformant query This architecture often includes also an SDMX registry that implements the general idea of a metadata registry The Census Hub Idea

23. Each National Statistics Institute (NSI) creates a set of non-disclosure data. The delivery of this data would be via an information hub that enabled data sharing on the Internet. Each NSI would provide web access to their data according to standard formats and technologies. A data user browses the hub to search for a dataset of interest using structural metadata (dimensions, attributes, code lists, etc). Data is retrieved directly from the NSI system to the Hub. The Census Hub Idea

24. The Pilot Project Architecture

25. Census Hub pilot project architecture The central Hub – Eurostat side The web service – NSI side The pilot hypercube Sex

26. Age

27. Current Activity Status

28. Geography

29. Data Sharing in Census Hub Query SDMX Data SDMX-ML WS NSI

30. The Pilot Project Architecture The Q uery builder constructs one or more SDMX queries that will be sent to the related NSIs web services through the W eb service client. When the Web service client receives the responses (in the format of a SDMX cross-sectional data message) from the queried web services, it forwards those to the Result aggregation manager . The Result aggregation manager puts together all the received SDMX data messages and sends the result to the D issemination transformer that makes a transformation from an XML format to HTML or CSV.

31. The Pilot Project Architecture The web service receives a SDMX query and forwards it to the SDMX q uery parser . The SDMX Q uery parser breaks down the query and sends it to the SQL query builder . The SQL query builder creates one or more SQL queries and sends them to D atabase . The result is assembled, by the SDMX-ML assembler , in a SDMX cross-sectional message that will be sent, by the web service, to the central Hub. NSI

32. The Pilot Project Architecture Statistics Portugal Architecture Model

33. The Pilot Project Architecture Statistisches Bundesamt Architecture Model

34. The Pilot Project Census Task Force (in the April 2007 meeting) agreed to explore the Hub solution and decided to launch a pilot project (DE, IE, IT and PT involved); Eurostat define some guidelines to this project: Simple hypercube in order to let NSI produce it quickly;

35. Data should comprise the following dimensions: Sex, Age, Current Activity Status and Territory;

36. A Data Structure Definition also provided

37. January 2008: start of the pilot project. Four countries decided to participate (Germany, Ireland, Italy and Portugal);

38. March 2008: preparation of requirement specification, functional and technical analysis;

39. April 2008: choice of one data hypercube and related breakdowns to use during the pilot; development of the Data Structure Definition (DSD);

40. June - September 2008: building of application modules (both Eurostat and NSI side); tests;

41. October 2008: evaluation report of the pilot; functional and technical analysis for the full 2011 Census Hub. The Pilot Project Roadmap

42. Eurostat has developed the central Hub and, at the beginning of February 2009, it will be accessible in a test environment . Italy, Portugal, Germany and Ireland have already setup the architecture Italy, Portugal and Ireland have produced documents (available on CIRCA) regarding their experience during the pilot phase ( http://circa.europa.eu/Members/irc/dsis/x-dis-xensus-hub/library?l=/census_documents_1/case_studies) Results of the pilot project

44. Moreover it was produced the Census Hub Web Service implementation Guidelines3 that explains how to build web services, using different IT technologies, capable of communicating correctly with the central hub. (http://circa.europa.eu/Members/irc/dsis/x-dis-xensus-hub/library?l=/census_documents_1/documents ) Finally it is important to highlight how sharing experience and software, between all the involved actors (Eurostat and NSIs), have allowed the reduction of production costs and development time. Results of the pilot project